libgocryptfs/fsck.go

275 lines
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package main
import (
"bytes"
"fmt"
"os"
"path/filepath"
"sort"
"strings"
"sync"
"syscall"
"github.com/hanwen/go-fuse/fuse"
"github.com/hanwen/go-fuse/fuse/nodefs"
"github.com/rfjakob/gocryptfs/internal/exitcodes"
"github.com/rfjakob/gocryptfs/internal/fusefrontend"
"github.com/rfjakob/gocryptfs/internal/tlog"
)
type fsckObj struct {
fs *fusefrontend.FS
// List of corrupt files
corruptList []string
// List of skipped files
skippedList []string
// Protects corruptList
listLock sync.Mutex
// stop a running watchMitigatedCorruptions thread
watchDone chan struct{}
// Inode numbers of hard-linked files (Nlink > 1) that we have already checked
seenInodes map[uint64]struct{}
}
func runsAsRoot() bool {
return syscall.Geteuid() == 0
}
func (ck *fsckObj) markCorrupt(path string) {
ck.listLock.Lock()
ck.corruptList = append(ck.corruptList, path)
ck.listLock.Unlock()
}
func (ck *fsckObj) markSkipped(path string) {
ck.listLock.Lock()
ck.skippedList = append(ck.skippedList, path)
ck.listLock.Unlock()
}
// Watch for mitigated corruptions that occur during OpenDir()
func (ck *fsckObj) watchMitigatedCorruptionsOpenDir(path string) {
for {
select {
case item := <-ck.fs.MitigatedCorruptions:
fmt.Printf("fsck: corrupt entry in dir %q: %q\n", path, item)
ck.markCorrupt(filepath.Join(path, item))
case <-ck.watchDone:
return
}
}
}
// Recursively check dir for corruption
func (ck *fsckObj) dir(path string) {
tlog.Debug.Printf("ck.dir %q\n", path)
ck.xattrs(path)
// Run OpenDir and catch transparently mitigated corruptions
go ck.watchMitigatedCorruptionsOpenDir(path)
entries, status := ck.fs.OpenDir(path, nil)
ck.watchDone <- struct{}{}
// Also catch non-mitigated corruptions
if !status.Ok() {
fmt.Printf("fsck: error opening dir %q: %v\n", path, status)
if status == fuse.EACCES && !runsAsRoot() {
ck.markSkipped(path)
} else {
ck.markCorrupt(path)
}
return
}
// Sort alphabetically
sort.Sort(sortableDirEntries(entries))
for _, entry := range entries {
if entry.Name == "." || entry.Name == ".." {
continue
}
nextPath := filepath.Join(path, entry.Name)
filetype := entry.Mode & syscall.S_IFMT
//fmt.Printf(" %q %x\n", entry.Name, entry.Mode)
switch filetype {
case syscall.S_IFDIR:
ck.dir(nextPath)
case syscall.S_IFREG:
ck.file(nextPath)
case syscall.S_IFLNK:
ck.symlink(nextPath)
case syscall.S_IFIFO, syscall.S_IFSOCK, syscall.S_IFBLK, syscall.S_IFCHR:
// nothing to check
default:
fmt.Printf("fsck: unhandled file type %x\n", filetype)
}
}
}
func (ck *fsckObj) symlink(path string) {
_, status := ck.fs.Readlink(path, nil)
if !status.Ok() {
ck.markCorrupt(path)
fmt.Printf("fsck: error reading symlink %q: %v\n", path, status)
}
}
// Watch for mitigated corruptions that occur during Read()
func (ck *fsckObj) watchMitigatedCorruptionsRead(path string) {
for {
select {
case item := <-ck.fs.MitigatedCorruptions:
fmt.Printf("fsck: corrupt file %q (inode %s)\n", path, item)
ck.markCorrupt(path)
case <-ck.watchDone:
return
}
}
}
// Check file for corruption
func (ck *fsckObj) file(path string) {
tlog.Debug.Printf("ck.file %q\n", path)
attr, status := ck.fs.GetAttr(path, nil)
if !status.Ok() {
ck.markCorrupt(path)
fmt.Printf("fsck: error stating file %q: %v\n", path, status)
return
}
if attr.Nlink > 1 {
// Due to hard links, we may have already checked this file.
if _, ok := ck.seenInodes[attr.Ino]; ok {
tlog.Debug.Printf("ck.file : skipping %q (inode number %d already seen)\n", path, attr.Ino)
return
}
ck.seenInodes[attr.Ino] = struct{}{}
}
ck.xattrs(path)
f, status := ck.fs.Open(path, syscall.O_RDONLY, nil)
if !status.Ok() {
fmt.Printf("fsck: error opening file %q: %v\n", path, status)
if status == fuse.EACCES && !runsAsRoot() {
ck.markSkipped(path)
} else {
ck.markCorrupt(path)
}
return
}
defer f.Release()
// 128 kiB of zeros
allZero := make([]byte, fuse.MAX_KERNEL_WRITE)
buf := make([]byte, fuse.MAX_KERNEL_WRITE)
var off int64
// Read() through the whole file and catch transparently mitigated corruptions
go ck.watchMitigatedCorruptionsRead(path)
defer func() { ck.watchDone <- struct{}{} }()
for {
tlog.Debug.Printf("ck.file: read %d bytes from offset %d\n", len(buf), off)
result, status := f.Read(buf, off)
if !status.Ok() {
ck.markCorrupt(path)
fmt.Printf("fsck: error reading file %q (inum %d): %v\n", path, inum(f), status)
return
}
n := result.Size()
// EOF
if n == 0 {
return
}
off += int64(n)
// If we seem to be in the middle of a file hole, try to skip to the next
// data section.
data := buf[:n]
if bytes.Equal(data, allZero) {
tlog.Debug.Printf("ck.file: trying to skip file hole\n")
f2 := f.(*fusefrontend.File)
nextOff, err := f2.SeekData(off)
if err == nil {
off = nextOff
}
}
}
}
// Watch for mitigated corruptions that occur during ListXAttr()
func (ck *fsckObj) watchMitigatedCorruptionsListXAttr(path string) {
for {
select {
case item := <-ck.fs.MitigatedCorruptions:
fmt.Printf("fsck: corrupt xattr name on file %q: %q\n", path, item)
ck.markCorrupt(path + " xattr:" + item)
case <-ck.watchDone:
return
}
}
}
// Check xattrs on file/dir at path
func (ck *fsckObj) xattrs(path string) {
// Run ListXAttr() and catch transparently mitigated corruptions
go ck.watchMitigatedCorruptionsListXAttr(path)
attrs, status := ck.fs.ListXAttr(path, nil)
ck.watchDone <- struct{}{}
// Also catch non-mitigated corruptions
if !status.Ok() {
fmt.Printf("fsck: error listing xattrs on %q: %v\n", path, status)
ck.markCorrupt(path)
return
}
for _, a := range attrs {
_, status := ck.fs.GetXAttr(path, a, nil)
if !status.Ok() {
fmt.Printf("fsck: error reading xattr %q from %q: %v\n", a, path, status)
if status == fuse.EACCES && !runsAsRoot() {
ck.markSkipped(path)
} else {
ck.markCorrupt(path)
}
}
}
}
func fsck(args *argContainer) {
if args.reverse {
tlog.Fatal.Printf("Running -fsck with -reverse is not supported")
os.Exit(exitcodes.Usage)
}
args.allow_other = false
pfs, wipeKeys := initFuseFrontend(args)
fs := pfs.(*fusefrontend.FS)
fs.MitigatedCorruptions = make(chan string)
ck := fsckObj{
fs: fs,
watchDone: make(chan struct{}),
seenInodes: make(map[uint64]struct{}),
}
ck.dir("")
wipeKeys()
if len(ck.corruptList) == 0 && len(ck.skippedList) == 0 {
tlog.Info.Printf("fsck summary: no problems found\n")
return
}
if len(ck.skippedList) > 0 {
tlog.Warn.Printf("fsck: re-run this program as root to check all files!\n")
}
fmt.Printf("fsck summary: %d corrupt files, %d files skipped\n", len(ck.corruptList), len(ck.skippedList))
os.Exit(exitcodes.FsckErrors)
}
type sortableDirEntries []fuse.DirEntry
func (s sortableDirEntries) Len() int {
return len(s)
}
func (s sortableDirEntries) Swap(i, j int) {
s[i], s[j] = s[j], s[i]
}
func (s sortableDirEntries) Less(i, j int) bool {
return strings.Compare(s[i].Name, s[j].Name) < 0
}
func inum(f nodefs.File) uint64 {
var a fuse.Attr
f.GetAttr(&a)
return a.Ino
}